957 research outputs found

    Double ionization of a three-electron atom: Spin correlation effects

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    We study the effects of spin degrees of freedom and wave function symmetries on double ionization in three-electron systems. Each electron is assigned one spatial degree of freedom. The resulting three-dimensional Schr\"odinger equation is integrated numerically using grid-based Fourier transforms. We reveal three-electron effects on the double ionization yield by comparing signals for different ionization channels. We explain our findings by the existence of fundamental differences between three-electronic and truly two-electronic spin-resolved ionization schemes. We find, for instance, that double ionization from a three-electron system is dominated by electrons that have the opposite spin

    Developing Multiplication Fact Fluency

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    Using specific components of three broad learning theories—cognitive, social-interactional, and behavioral—students in 3rd, 4th and 5th grade classrooms were given multiplication fact fluency instruction over a period of five weeks for 10-15 minutes each day. Two different approaches were utilized with two distinct groups of students for the purpose of comparing different approaches to fluency development. Results indicate that students using a strategy-based approach for fluency development by means of instructional tasks emphasizing social-interactional and cognitive theories (particularly Bruner’s theory of Modes of Representation) increased multiplication fact fluency, with a greater degree of consistency, than students using a drill-based approach emphasizing behavioristic techniques such as repetition and memorization

    Restricted space ab initio models for double ionization by strong laser pulses

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    Double electron ionisation process occurs when an intense laser pulse interacts with atoms or molecules. Exact {\it ab initio} numerical simulation of such a situation is extremely computer resources demanding, thus often one is forced to apply reduced dimensionality models to get insight into the physics of the process. The performance of several algorithms for simulating double electron ionization by strong femtosecond laser pulses are studied. The obtained ionization yields and the momentum distributions of the released electrons are compared, and the effects of the model dimensionality on the ionization dynamics discussed

    Expression and mutational analysis of Nm23-H1 in liver metastases of colorectal cancer.

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    It has been proposed that nm23-H1, a candidate suppressor gene for metastasis, plays an important role in metastasis formation of human tumours. In order to investigate its role in the progression of colorectal cancer, we analysed 22 liver metastases of this malignancy with respect to mutational changes, loss of heterozygosity and expression levels of nm23-H1. Although genetic alterations in nm23-H1 have recently been described in those colorectal adenocarcinomas which give rise to distant metastases, we were unable to detect any mutation in the coding sequence of nm23-H1 in the metastatic tissue itself. We further analysed the metastases with respect to allelic deletions at the chromosomal locus of nm23. However, no loss of heterozygosity could be detected in ten informative cases. Moreover, the mRNA expression levels of nm23-H1 in the metastatic tissues were not significantly different from those in normal colon mucosa. Thus, although nm23-H1 might be involved in metastasis suppression of certain tumour types, in colorectal tumour progression its role remains to be determined

    Technical Performance and Energy Intensity of the Electrode-Separator Composite Manufacturing Process

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    AbstractEnergy storage is one of the key technological factors that determine the success of a sustainable future. Especially green mobility concepts for electric or hybrid electric vehicles highly depend upon storage technologies with high energy density and light-weight materials. At the same time, innovative production processes should be conceived that ensure energy and resource efficient manufacturing of these energy storage devices. This paper focuses on the technical as well as dynamic energetic performance analysis and evaluation of an innovative electrode-separator composite manufacturing process of lithium-ion batteries for automotive applications. The technical performance indicators such as battery capacity and the energy intensity of the manufacturing process are highly dependent upon process parameters, machine and product design. Hence, in-depth process knowledge must be acquired to understand interdependencies between all system components. Thus, the manufacturing process is analysed in terms of its dynamics, and correlations between process parameters, process energy demand and final product properties are assessed. The resulting knowledge is important for the subsequent design of large-scale products and processes involved design, as well as for characterisation of the manufacturing process for life cycle inventory databases or life cycle costing calculations

    Attractive and repulsive factors act through multi-subunit receptor complexes to regulate nerve fiber growth

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    In the nervous system, attractive and repulsive factors guide neuronal growth, pathfinding and target innervation during development, learning and regeneration after injury. Repulsive and growth-inhibitory factors, such as some ephrins, semaphorins, netrins and myelin-associated growth inhibitors, restrict nerve fiber growth, whereas neurotrophins, and other ephrins, semaphorins and netrins attract fibers and promote neurite growth. Several of these guidance molecules also play crucial roles in vasculogenesis, and regulate cell migration and tissue formation in different organs. Precise and highly specific signal transduction in space and time is required in all these cases, which primarily depends on the presence and function of specific receptors. Interestingly, many of these ligands act through multi-subunit receptor complexes. In this Commentary, we review the current knowledge of how complexes of the receptors for attractive and repulsive neurite growth regulatory factors are reorganized in a spatial and temporal manner, and reveal the implications that such dynamics have on the signaling events that coordinate neurite fiber growth

    Cross-cultural Socialization into a Common Profession: Exploring how Nursing Students in Taiwan and in the U.S. Narrate Professional Identity

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    This discussion will draw on a series of written stories and commentaries on professional values in nursing for a cross-cultural pragmatics study of US nursing students in North Carolina and Chinese nursing students in Kaohsiung, Taiwan. We explore cultural differences in salience as a pragmatics construct for a professional construct important in nursing, that of caring. The nursing students were not in direct contact with each other except through written stories and commentaries:The Chinese nurses first wrote their thoughts in Mandarin and then translated them into English, after which the US students read and responded to them. The nursing students from both countries assumed that they shared constructs of what constituted professional values in nursing. However, our discussion will question the degree to which they shared common ground and assigned similar salience to the construct. We conclude that the Chinese and the US student nurses erroneously assumed that they shared each other’s understanding of ‘caring,’ underestimating the differences in work environment and cultural expectations. We also propose that they are readily capable, through communication, of recalibrating their reference frames once made aware that they differ.Boyd H. Davis: [email protected] Thiede: [email protected] K. Smith: [email protected] Davis is Bonnie Cone Professor of Teaching and Professor for linguistics at the University of North Carolina – Charlotte. Her research uses socio-historical approaches to the study of narrative, pragmatics and stance in medical discourse and Alzheimer’s speech, online discourse, and the creation of digital corpora.Ralf Thiede is Associate Professor for linguistics at the University of North Carolina – Charlotte. He teaches courses in linguistics, cognitive science, and medieval British literature. His research focuses on interfaces: school grammar with syntactic theory, semantics with syntax, linguistic faculty with cognition, usage with control.Mary Smith is Program Coordinator, Healthcare Continuing Education, Central Piedmont Community College in Charlotte, NC. She develops, implements, and evaluates Allied Health Continuing Education Programs and creates online curriculum for Nursing Assistants.Boyd H. Davis - The University of North Carolina, CharlotteRalf Thiede - The University of North Carolina, CharlotteMary K. Smith - Central Piedmont Community College, Charlotte162

    Synthesizing qualitative and quantitative evidence on non-financial access barriers: implications for assessment at the district level

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    INTRODUCTION: A key element of the global drive to universal health coverage is ensuring access to needed health services for everyone, and to pursue this goal in an equitable way. This requires concerted efforts to reduce disparities in access through understanding and acting on barriers facing communities with the lowest utilisation levels. Financial barriers dominate the empirical literature on health service access. Unless the full range of access barriers are investigated, efforts to promote equitable access to health care are unlikely to succeed. This paper therefore focuses on exploring the nature and extent of non-financial access barriers. METHODS: We draw upon two structured literature reviews on barriers to access and utilization of maternal, newborn and child health services in Ghana, Bangladesh, Vietnam and Rwanda. One review analyses access barriers identified in published literature using qualitative research methods; the other in published literature using quantitative analysis of household survey data. We then synthesised the key qualitative and quantitative findings through a conjoint iterative analysis. RESULTS: Five dominant themes on non-financial access barriers were identified: ethnicity; religion; physical accessibility; decision-making, gender and autonomy; and knowledge, information and education. The analysis highlighted that non-financial factors pose considerable barriers to access, many of which relate to the acceptability dimension of access and are challenging to address. Another key finding is that quantitative research methods, while yielding important findings, are inadequate for understanding non-financial access barriers in sufficient detail to develop effective responses. Qualitative research is critical in filling this gap. The analysis also indicates that the nature of non-financial access barriers vary considerably, not only between countries but also between different communities within individual countries. CONCLUSIONS: To adequately understand access barriers as a basis for developing effective strategies to address them, mixed-methods approaches are required. From an equity perspective, communities with the lowest utilisation levels should be prioritised and the access barriers specific to that community identified. It is, therefore, critical to develop approaches that can be used at the district level to diagnose and act upon access barriers if we are to pursue an equitable path to universal health coverage

    Enantiopure Cyclopropane-Bearing Pyridyldiazabicyclo[3.3.0]Octanes As Selective α4β2-Nachr Ligands

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    We report the synthesis and characterization of a series of enantiopure 5-cyclopropane-bearing pyridyldiazabicyclo[3.3.0]octanes that display low nanomolar binding affinities and act as functional agonists at α4β2-nicotinic acetylcholine receptor (nAChR) subtype. Structure-activity relationship studies revealed that incorporation of a cyclopropane-containing side chain at the 5-position of the pyridine ring provides ligands with improved subtype selectivity for nAChR β2 subunit-containing nAChR subtypes (β2∗-nAChRs) over α4∗-nAChRs compared to the parent compound 4. Compound 15 exhibited subnanomolar binding affinity for α4β2-and α4β2∗-nAChRs with negligible interaction. Functional assays confirm selectivity for α4β2-nAChRs. Furthermore, using the SmartCube assay system, this ligand showed antidepressant, anxiolytic, and antipsychotic features, while mouse forced-swim assay further confirm the antidepressant-like property of 15
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